cub conprestion

Anonymous-0 · Feb 16, 2011

what should comprestion be doesnt want to run acts like it doesnt have enought to pull up gas to cylinders it reads from 25 30 35 25 put a little oil in each plug hole and it gains 5 to 10 lbs

billde · Feb 16, 2011

If that is an accurate reading, it probably won't pull fuel. Any chance you have an air restriction? Pull the air cleaner hose off the carb and recheck. May also want to set the valve lash .017-.019.

Wayne in MN · Feb 16, 2011

Do the compression test with the throttle wide open & air cleaner disconnected to allow maximum air into each cylinder.

CraigChristian · Feb 17, 2011

Valve lash on a Cub should be .013" - .015" cold but at those numbers, I'd suspect a rebuild is in order !!! It should be at least 90 #/cylinder with maybe a 5-10% variance among the cylinders. Craig

billde · Feb 17, 2011

I stand corrected valve lash is .013 to .015.

dhermesc · Feb 17, 2011

With that low of compression I'm suprised it even runs. I would start by pulling the head and checking out the valves.

Dave H (MI) · Feb 17, 2011

Way to low. It will run with less than 90 per cylinder if all other conditions are favorable but at your readings I am surprised if it starts at all. Time to figure out why so low.

El Toro · Feb 17, 2011

You should have the cylinders measured for wear. You probably need the cylinders bored
oversize. Your local auto machine shop can tell you if the wear is beyond specs. Hal

cub conprestion

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Anonymous-0

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